Conventionally, active-energy-beam-hardened type resin compositions, which are hardened through irradiation with an active energy beam such as a UV beam or an electron beam, have been practically used in the field of printing inks;
the field of coatings for plastic products, metallic products, furniture, and other products; the field of electrical insulation, e.g., insulating varnishes, insulating sheets, laminated boards, printed substrates, resist inks, and semiconductor-sealing agents; and other fields including the fields of adhesives, sealants, sizing agents for paper making, and lining materials. The resin compositions are utilized in such a variety of fields because they have the following advantages: (1) solvent-free and low environmental pollution; (2) remarkably high hardening speed to provide enhanced productivity of corresponding products; (3) remarkably low change in volume before and after hardening due to hardening as 100% solid matter; and (4) wide range of on-going development for coatings for plastics, paper, and inorganic materials; adhesives; and sealants due to low thermal loss by substrate materials or no thermal influence to substrate materials.
For example, epoxy (meth)acrylate resins which are obtained through ring-opening reaction of acrylic acid or methacrylic acid with epoxy groups of an epoxy resin are widely used as energy-beam-hardened type coatings, inks, and adhesives having the above-described characteristics. However, these widely used epoxy (meth)acrylate resins have disadvantages such as high degree of hardness and brittleness or high degree of shrinkage during hardening. For example, in the case in which such a resin is used as a printing ink for paper, printed ink generates cracks when the printed paper is folded. Also, in the case in which the resin is used as a coating for metal sheets of iron, aluminum, etc., the resultant film may easily generate cracks due to brittleness when the coated metal sheets is subjected to bend-processing to result in an unsuccessful processing, or adhesion of the coating to the metal sheets of iron, aluminum, etc. may sometimes be poor.
To overcome the disadvantages of such active-energy-beam-hardened type epoxy (meth)acrylate resins and active-energy-beam-hardened type epoxy resins, an object of the present invention is to provide block copolymers for hardenable resin compositions which provide a coating film exhibiting appropriate flexibility and exhibiting excellent adhesion, water resistance, and heat resistance, and remarkably excellent solvent resistance and gloss, and to provide a variety of hardenable resin compositions containing the copolymers.